Linek Małgorzata
Faculty of Civil Engineering and Architecture, Kielce University of Technology, Tysiąclecia Państwa Polskiego Street 7, 25-314 Kielce, Poland.
Materials (Basel). 2022 May 20;15(10):3673. doi: 10.3390/ma15103673.
The impact of aircraft on airport pavements is varied and closely related to their operational durability. The article presents the impact of the annealing process related to the forced impact of airplanes on airport pavements. The composition of cement concrete with ceramic dust, which is characterized by increased thermal resistance, has been proposed. Two research cycles were programmed, differentiated by the annealing scheme and the way in which the temperature influences the annealing time. Samples stored at a temperature of 20 ± 2 °C were subjected to testing. The tests were carried out for two diagrams: A and B. The first-diagram A-included the continuous impact of the flue gas stream on the samples for a period of 350 min with a test step every 25 min. For the second-diagram B-the samples were alternately heated (1 min) and cooled (15 min). The influence of the proposed pavement mix on changes in the internal structure of cement concrete and the increase in its resistance to high temperatures was determined. In the microstructure of the CC-1 concrete matrix, it was found that there were plate-granular portlandite crystals up to 10 µm in size and ettringite crystals with a length of 8 µm. In the CC-2 concrete, the ettringite crystals were less numerous and had a length of up to 5 µm, there were also continuous contact zones between the aggregate grains and the cement matrix (diagrams A). The alternating annealing/cooling (diagram B) resulted in the ettringite crystals in the CC-1 matrix being up to 10 µm long, and in the CC-2 concrete up to 7 µm long. The contact zone between the aggregate grain and the matrix in CC-2 concrete was continuous, and the microcracks in CC-1 concrete were up to 8 nm. Regardless of the heating diagram, in the surface zone, there were larger microcracks in the CC-1 concrete than in the CC-2 concrete. For diagram A they were 14 µm and 4 µm and for diagram B they were 35 µm and 5 µm, respectively. It was found that concrete with ceramic dust is characterized by a lower and more stable temperature increase. In scheme A, the average temperature increase on the heated surface ranged from 46 °C to 79.5 °C for CC-1 concrete, and from 33.3 °C to 61.3 °C for CC-2 concrete. However, in scheme B, the temperature after 350 heating cycles for CC-1 concrete increased to 129.8 °C, and for CC-2 concrete to 116.6 °C. After the cooling period, the temperature of CC-1 and CC-2 concrete was comparable and amounted to 76.4 C and 76.3 °C, respectively. CC-2 concrete heats to lower values, and favorable changes in internal structure translate into higher strength and durability (after 350 heating cycles according to scheme A, the strength of CC-1 concrete was 67.1 MPa and of CC-2 concrete 83.9 MPa, while in scheme B, respectively, 55.4 MPa for CC-1 and 75 MPa for CC-2).
飞机对机场跑道的影响是多方面的，且与跑道的运营耐久性密切相关。本文介绍了与飞机对机场跑道的强制冲击相关的退火过程的影响。提出了一种以提高耐热性为特点的含陶瓷粉尘的水泥混凝土组成。规划了两个研究周期，通过退火方案以及温度对退火时间的影响方式加以区分。对储存在20±2°C温度下的样品进行了测试。测试针对两个图表进行：A和B。第一个图表A包括让烟气流持续冲击样品350分钟，每25分钟进行一次测试步骤。对于第二个图表B，样品交替加热（1分钟）和冷却（15分钟）。确定了所提议的路面混合料对水泥混凝土内部结构变化及其耐高温性提高的影响。在CC - 1混凝土基体的微观结构中，发现有尺寸达10μm的板状粒状氢氧化钙晶体以及长度为8μm的钙矾石晶体。在CC - 2混凝土中，钙矾石晶体数量较少，长度达5μm，集料颗粒与水泥基体之间也存在连续的接触区（图表A）。交替退火/冷却（图表B）使得CC - 1基体中的钙矾石晶体长达10μm，在CC - 2混凝土中长达7μm。CC - 2混凝土中集料颗粒与基体之间的接触区是连续的，CC - 1混凝土中的微裂纹达8nm。无论加热图表如何，在表面区域，CC - 1混凝土中的微裂纹比CC - 2混凝土中的更大。对于图表A，它们分别为14μm和4μm，对于图表B，它们分别为35μm和5μm。发现含陶瓷粉尘的混凝土具有较低且更稳定的温度升高特性。在方案A中，CC - 1混凝土加热表面的平均温度升高范围为46°C至79.5°C，CC - 2混凝土为33.3°C至61.3°C。然而，在方案B中，CC - 1混凝土经过350次加热循环后的温度升至129.8°C，CC - 2混凝土升至116.6°C。冷却期后，CC - 1和CC - 2混凝土的温度相当，分别为76.4°C和76.3°C。CC - 2混凝土加热到较低值，内部结构的有利变化转化为更高的强度和耐久性（根据方案A经过350次加热循环后，CC - 1混凝土的强度为67.1MPa，CC - 2混凝土为83.9MPa，而在方案B中，CC - 1分别为55.4MPa，CC - 2为75MPa）。
